Practicality aside, being able to read and understand a map is an important analytical skill. Mapping has been a part of our lives since the very first explorers set forth to chart the lands beyond their countries. After centuries of such adventures, very little of the Earth's surface is yet uncharted. Orbiting satellites also have been making many detailed maps of the Earth's surface. However, much of the most exciting mapping being done today happens from our explorations away from the Earth! Several robotic space missions have traveled to other planets to map their surfaces. Most recently, the Magellan space probe which orbited Venus made a detailed radar map of its terrain, obscured by Venus' thick atmosphere. The CfA Redshift Survey is a project of over a decade which is mapping the galaxies of the entire Universe!

Whether a map is of a classroom, a city, a planet, or an Universe, the same basic knowledge is required to understand the information it contains: scale, orientation, angles, and measurement.
In this chapter, we practice reading maps, first of our nearby surroundings, then of our town, and then of the Earth and stars.
We begin this topic by using maps, then learning how to make our own.

Topic 1: Reading Maps

Whether to get across town or across the world, maps are crucial for navigation. They can help us discover the distances between objects and their relative orientation to one another.

The ideas of following direction and relating to a two-dimensional representation of a landscape are to be introduced first with a fun scavenger hunt. The chapter will then move on to political maps, and then see how topographical maps describe terrain.

Activity 4-1: Scavenger Hunt

This activity is best suited to younger students.

Scavenger hunts are always fun, but in this hunt, the rewards include not just the "goodies" found on the course, but also the skill of following a map.

Materials: An interesting, yet safe and supervised, course for the hunt; a simple, handmade map of the course; small prizes like toys, trading cards, booklets of stories, etc.

1. Lay out the course for the scavenger hunt on a field or playground. Make a map with the locations of the goodies. Be sure to include enough reference points like buildings, trees, rocks, and playground equipment. (sample map)

2. Split the class into small teams and give each student a map of the course. It would be best for the "hunt" to be non-competitive, so plan different maps for each group with different treasures - even if they cover the same area. The focus should be on the map, not the clock or the other teams.

3. Discuss the map with the students to eliminate any areas of confusion, and let the hunt begin!

4. After the hunt, make sure all of the treasures were found. If one was missed, analyze the map containing it with the entire class, and go find the missing booty.

Discussion

Were the students able to find all of the goodies? Could they find all of the reference points? Which ones were easier to find? Were they able to find topographical features like hills. Would compass directions help? What about distant landmarks? What makes a good map? What should a map convey? Are all maps meant for the same purpose? How might the map had been different if the students were driving cars or flying planes instead of walking around?

Activity 4-2: Follow a Map of the Town

This activity may be done in small groups.

Instead of looking at a map of a small area, like the playground, we will look at a larger area: our home town or city. See how many landmarks the students can find. Can they find where they live? Can they find their school? You should make a list of places for each student or group to find. The type of places which can be found depends greatly on the type of map available.

Materials: Road map of city or town; list of places, landmarks, or streets to find; rulers.

1. Find a good map of the local area. It can be any kind of map: political, road, sight-seeing, etc. The town or city hall or the local Chamber of Commerce may be able to help. You could also find maps to photocopy in the school or public library.

2. Make a list of places which each student or group should locate, such as the town or city hall, public library, police station, barber shop, pharmacy, etc.

3. Give a copy or portion of the map to each student or group. How many of the places can they find? Can they find where they live?

4. This is a good place to introduce the concept of "scale". Show the students where the scale is on the map and what it means. Provide rulers so they can practice measuring and determining distances. When the students have found some locations, ask them how far it is between any two of them.

Discussion

If one map has a scale of "1 inch = 1 mile" and another has "1 inch = 10 miles", which map covers more area? Which map can show more detail? Is a map with more detail always better? What kind of information might a political map have which a topographic map might not? What kind of information would a nautical chart have? Can anyone think of a problem with making a map of the entire Earth? Hint: is the Earth flat like the map?

Activity 4-3: Topographic Maps

This activity assumes you are in the United States, but similar surveys and maps exist in other countries as well.

In 1960, the federal government conducted a complete topographical survey of the United States. The commission responsible for this survey, the United States Geological Survey Commission, has field-checked and updated the Survey several times in the years since. The Survey maps show features of the land, like lakes, ponds, rivers, and streams, and man-made landmarks like permanent buildings, roads, churches, graveyards. They are very detailed, being of the scale 1:24,000; one centimeter on the map represents 24,000 centimeters (240 m or 0.24 km) on the Earth (in English units, one inch represents about 0.38 miles). Neither the roads nor the buildings are labeled, however; these maps are intended to record surface features, especially variations of altitude. To do this, there are contours drawn on the maps, to indicate 10-foot variations in altitude. As a result, these maps are able to convey a sense of the three-dimensional lay of the land. In this activity, we will compare the Survey maps with the land they represent.

Materials: Topographic map available from the U.S. Geologic Survey (details below).

1. Obtain a Survey map for an area around or near the school where the class can visit for an hour or so. The Survey maps may be available in nearby public or college libraries. They are also available for $2 each from the United States Geological Survey Commission, Denver, Colorado 80225.

2. Make a photocopy of the map or parts of the map for each student. Discuss the various symbols and the contours. Make a list of obvious geographic features on the map which should be apparent at the site.

3. Visit the site with the class. It can be the school grounds themselves, or somewhere near enough for a field trip. See how many of the features on the map are apparent at the site. Did the map help to visualize the site before the visit? Try to find a feature at the site which does not match the map. Why might this be?

Discussion

Who might use a map like this? Is it a good road map? Does it should political boundaries like precincts, counties, and states? What sorts of uses would this map have that, say, a sightseeing map wouldn't?
Why bother recording altitude? Can you think of way other than contours to record it? If the contours on a hill are closer together, does that mean the hill is more or less steep than one whose contours are farther apart?

Topic 2: Making Maps

Now that the students have had some experience using and
interpreting maps, the next logical step is to try to make some.
We'll start small- literally - by mapping a small, familiar area, the classroom. We'll then venture outside and map the school grounds.

Activity 4-4: Making and Using a Trundle Wheel

It is suspected that in the making of the precise dimensions of the Egyptian Pyramids, architects used a device known as the trundle wheel. We have often used rulers or meter sticks to measure distances, but this requires several steps: placing the ruler down, marking the far end of the ruler, lifting the ruler up and putting the close end on the mark, marking the far end, etc., until the distance is measured. Even using a flimsy tape measure requires several people to hold one end firm, to keep the tape from flipping, to measure the end, etc. The trundle wheel, however, relies on the simple fact that a circle with a known circumference can be used as a ruler. The circumference is the distance around any circle. Take a string one foot long and bring the ends together to form a circle -- the circumference of this circle is one foot. Rolling a circle with a known circumference along on its edge and counting how many times the circle can go around will tell you how many feet make up that distance you rolled it.

1. Making circles of different circumferences requires knowing the radii of the circles. The relation, Circumference = 2 x radius x p is used. We've figured out circles for circumferences of 1 foot, 3 feet, and 18 feet by calculating their radii. These trundle wheel sizes are convenient for measuring distances as big as rooms or as small as the distances between desks. For the 1 ft trundle wheel, spread the two legs of the compass such that one end points to the zero line on the ruler and the other lines up with a little less than 2 inches (the radius). Lock the compass if you can, otherwise, be careful not to accidentally readjust them. Firmly stick the pin end of the compass into the cardboard and swing the pencil end around on the cardboard outlining a circle.

2. Carefully, with scissors or with a blade, cut out the circle. With a dark marker, make one straight line connecting the center to one edge of the circle. This will help you count how many circumferences the wheel has traveled.

3. To the center of the circle in the compass pin hole, fasten one end of the meter stick or the cardboard strip with a brass fastener.

4. Repeat those steps for the 3 ft circumference circle, but spread the compass points to a little less than 5.75 inches. The 18 ft circumference circle requires a bit of string cut to 2.87 feet. One end of this string is held firmly onto the cardboard while the other end of the string is pulled taut and held with a pencil. By swinging the string around on the cardboard and marking with the pencil where the end of the string meets the paper, you will have another circle to cut out. Then follow the rest of the steps to make it a trundle wheel.

5. Start measuring by lining the marker line pointed down with the ground where you want to begin the measurement. Roll the wheel along, counting how many times the marker line hits the floor. NOTE: Because the shape of the circle is a problem for reaching into corners of the room, simply start room measurements with the wheel edge touching the wall and roll to other end of the room until the wheel touches the other wall. Since from the edge to the center of the wheel is defined as the radius of the wheel, and since you had to line the wheel up with the edge twice, add twice the radius of the circle to any measurement made from corner to corner.

6. Practice measuring the size of the blackboard, the length of the room, the distance to first base on the kickball field, the height of students in the class. Compare the measurements with those gotten from laying down meter sticks.

Discussion

Are the trundle wheels easier to use than the meter sticks? Are the measurements different? Can students make their own wheels of different sizes using the circumference relationship to the radius? What are the advantages and disadvantages of the trundle wheel? Can students think of other shapes which might be good measuring tools?

Activity 4-5: Mapping the Classroom

For our first mapping exercise, we'll start small- literally- by mapping the classroom. First we'll examine the room, and discuss the objects in it. Then we'll build a scale model on a large sheet of paper. By tracing the objects we've placed on the paper to represent things in the room, we will have created our first map. The students can then develop a key to represent all of the objects in the room, and then they can make their own versions using their key.

1. Students should measure the sizes of the classroom and sizes of a few major pieces of furniture.

2. The class should sit around the chart paper cut about 9 x 4 feet. This paper represents the floor of the classroom and on will be placed representations of the objects in the classroom. Mark the length and the width of the classroom.

3. Look around the room and discuss the objects in it. Which objects are the same size? Which is the smallest? Are all of the objects the same shape? Students can make up a key which could be useful to themselves or others for this map and include it. For example, all desks could be represented by squares, chairs by circles, and so on.

4. Students can start mapping by arranging blocks of wood on the chart paper to represent the various pieces of furniture in the classroom. It may help to start with a few reference points such as the teacher's desk and the classroom door. When students have completed placing the blocks, they should trace the outline of each block onto the chart paper before putting them away.

5. Working either alone or in small groups and using the large chart paper as a guide, each student should then make his own map of the classroom on construction paper or oaktag. Rulers should be used to make straight lines and stencils to make circles, squares, and rectangles. How can they draw these objects so that the map will look like their classroom? If they show this to their parents, will they know how to locate their desk when visiting? What other information will this give to others? How could they improve the map? How can they make it look attractive?

6. Older students should try to represent objects to scale, perhaps using graph paper.

Discussion

What reference points were the most helpful when starting to map the classroom? Why? How does a key simplify making the map? Would it be more or less work to try to capture the distinct shape of each and every piece of furniture? When might it be necessary to record each shape? How does scale help one make sense of a map? Classes from different rooms could team up, exchange maps, and try to find their partners' desks. Visiting parents could try to use the maps to find their children's desks.

Activity 4-6: Perspective and Reference Points

As students begin to make maps, the importance of scale and perspective become clear.

1. Have the students look at the teddy bear on a stool in the center of the room. They can draw it and compare perspectives. Move the students so they view it from a different perspective. How does this affect what they see?

2. Students look at a very large picture which has been divided into four numbered quarters. They work in four groups, each student drawing the assigned section of the picture in a variety of paper sizes. When the student finishes, he finds a person from each of the other groups and they put them together. Students may analyze the results and find another way to work together to do a better representation.

3. Place various balls on a table. Darken the room and shine a light on the balls. Have students move around the table viewing the balls. They can stoop down low or stand up high on a chair to gain different perspectives. They may then discuss how these objects looked from a variety of reference points.

Discussion

How does measuring with tools help us to make a map? Does it make any difference where you stand when you make a map? Do objects look smaller from one place than from another? How does this effect your map? How can this help students in their map making? If students make another map of their playground (Activity 4 of this topic) will they do it differently? How can they use the measuring reference points in making maps? Would it change the way you made a map if you stand in another place to make it? How can you devise a system to represent the area and the objects in it so that they will be the same relative size or scale on your maps?

Activity 4-7: Mapping the School Grounds

The move outside provides students with different mapping challenges; scale, elevation, and topology take on added importance. Students learn by developing their own techniques for showing these; only when they have experienced this, they will benefit from materials for measurement of elevation such as large rods and levels. Through representations they will increasingly see the relationships between the three-dimensional world and the two-dimensional symbols which represent it on their maps.

When mapping a large area outside, such as the school yard, what tools will help you to make a map? Can you show how far away objects are after you measure them? Does it matter if you move around or should you stand in the same place? How can you use the compass to help you place objects? How can you represent directions accurately? How could you show the hilly parts of the land.

Materials: Large sheets of paper (one for each group of two students), with outline of school grounds and a few key features; pencils; measuring devices; yardsticks; trundle wheels, string; directional compasses.

1. Students should work in pairs standing in the center of the school grounds. They should measure and record the distances and directions to different objects on a map.

2. The students should discuss and compare their maps with the others. Do the maps look the same? If not, what makes them different? Are some distance determination techniques better for some objects (or some distances) than for others?

3. Students should note differences in topography and find a way to represent these differences? What else might help them to do this?

4. Students may wish to use materials such as clay, sand, or blocks to represent elevations. This may help them to find a way to represent these area on a two-dimensional map. How many ways can they show this change in terrain? Could colors, shapes, different kinds of lines show height?

Discussion

Students discuss their results. Were their maps similar? What problems did they encounter? How did they represent changes in elevation? What about various surfaces? How did they established directions? What kind of symbols did they use?

Activity 4-8: Mapping the City or Town

The step to mapping a larger area is the next in our investigation of mapping. Representing one's school and playground on a large map allows students to trace their routes to school by moving model cars and buses on the map. The streets represented may lead to major buildings such as libraries, fire and police stations, and town and city halls. Directionality may be established and a compass rose included in the map. Students may work from a map of their town which has been enlarged and then enlarge that again. Students may map a route to a playground or other area of interest and then walk that route together.

How could students help to map an area when the whole area cannot be seen? What materials would be helpful to use in making such a map? What unit of measure would be appropriate to use? If the school is the focus point and placed at the center of the map, how could students represent it? What other buildings would they want to represent on this map? What about other areas of their town? How could they make a very large map even large enough to walk on? How could they determine directions?

Materials: One large sheet (3'x 8') of heavy paper from standard 3' roll for each group; wide tape; yardstick; pencils; markers; photographs of buildings; large piece of heavy plastic to cover map; blocks of wood; map of students' town or city (enlarged to largest size possible on large capacity copy machines); plastic figures and cars; oaktag; glue.

1. Students discuss their school location and its proximity to other areas of interest in their town or city. They decide which buildings, areas and landmarks are important to include in a map of their area.

2. Students see a map of their town or city. This can be placed on the floor and students may sit around it. They look for their school and discuss the surrounding area such as streets and parks. They locate other buildings of importance and note the relative distance to their school. They discuss making a larger size map.

3. Some groups may want to work on streets and others may want to show playgrounds and ponds or lakes. They use markers to color the map. Three dimensional buildings may be made by drawing a building on oaktag. Cutting it out and standing it upon the fold at the bottom and supporting it with a strip of oaktag. These may be glued to the map.

4. When the map is finished, all students gather around it sitting in a circle and discuss this map and the experience shared in making it. They may add a compass rose. How is distance represented?

5. Discuss and compare the units of measure used in measuring the classroom or playground. Are they able to find a route they take to school? Using figurines to represent the students, could the class find a route to walk to the city hall or library. Would this route be different if going by car? Discuss taking a trip together using this map as a guide and test the route with figurines. Can the class predict how long such a journey would take? Can they devise a system to help them make an accurate prediction?

6. Students should walk to a designated area after making this map. This may be useful in visiting the library or the town hall or an historical site.

Discussion

Was this activity helpful to the students? In what ways? If they had to map an area foreign to them, how might they start? How would they measure large distances? Can the students find their own streets? If so, can they locate where their houses should be? If students were building a new town or city, how would they plan it? What would they include? exclude? What would they do differently?

Topic 3: Coordinate Systems

A coordinate system is just a way of systematically denoting and labeling points in space. Numbered aisles in supermarkets, grids on road maps, and lines of latitude and longitude on the Earth are all coordinate systems which we use every day. Coordinate systems are usually based on two lines, or axes, which are most often perpendicular to one another. In a city, for instance, one building may be "two blocks north and four blocks east", from another, in which case the compass directions of north and east are used as a basis for the grid of the city.

Activity 4-9: Reference Directions on the Earth

This activity requires a sunny day.

On the Earth, we use the directions of the compass for reference: Boston is north and east of New York, San Diego is south of Los Angeles. Canada is north of the United States and Mexico is south. The direction "north" is defined as the direction from any point on the globe towards the North Pole, where the axis of rotation of the Earth sticks out of the surface in the Northern Hemisphere. Similarly, "south" is towards the South Pole. We usually look at maps and globes where North is on the top. Why might this be? Are the two hemisphere's equally populated? Do you think " north is up" seems natural to people in Australia?

If one faces north and extends ones arms straight out to the sides, the left hand points to the west and the right to the east. Looking at a compass rose, one can remember this because the "W" of west and the "E" of east spell a word - "WE" - if they are properly aligned - "EW" is not a word! The Earth is spinning about its axis such that its surface moves eastward. This is why the Sun and Moon and the stars all rise on the eastern horizon, move westwardly through the sky, and set on the western horizon.

In this activity, we use the midday shadow to find true north, much as in the activity "Sun Shadows" of Chapter 1. If there is not sufficient time (or suitable weather) to use the shadow stick, a compass may be used instead, but keep in mind that the compass points towards magnetic north, not towards the North Pole of the Earth.

1. Using the shadow stick, determine the direction of north, which will correspond to the shortest (midday) shadow and mark this line on the large piece of paper. Secure the paper from the wind with a rock or brick..

2. Draw a line perpendicular to the north-south line. This is the east-west line. Mark each cardinal direction on the paper.

3. Have four students stand a few paces from the paper, one at each or the cardinal directions. Have the class name the direction at which each is standing.

4. Now have four more students stand at the same distance, but have each one stand between two at cardinal points. These students will be standing at northeast, southeast, southwest and northwest. Draw two diagonals on the paper and mark these directions.

5. Now have the class stand near the paper with the compass rose. Look around the school yard for reference points like hills, swingsets, jungle gyms, buildings, etc. Also look for distant landmarks; is there a city nearby? tall buildings on the horizon? or maybe some towering overhead! Determine the directions to these points, with the aid of the compass we've drawn on the paper.

Discussion

Is north always the same direction for everyone? What are the advantages of using such a "global" coordinate system? Are there any disadvantages Why not just use directions like "three blocks to the left" or "a mile and a half to the right"? Do these directions make assumptions about the traveler's original position and orientation? Are these directions better for local areas or larger areas?
If northeast (NE) is halfway between north and east, where might north by northeast (NNE) be? Where would south by southwest SSW be? If something is northeast of you, what direction are you from it?

Activity 4-10: Mapping on a Grid

This activity will introduce the students to mapping on a grid. While most grids we map by are made of invisible, imaginary lines, the lines of our grid in this activity are clearly visible, the cracks between linoleum floor tiles. Having placed objects on such a grid, the students can then try mapping the area on some graph paper, essentially a scaled down version of the grid. Once the concept of a map on a grid is understood, specific grids like latitude and longitude should make more sense to the students. A great game to play with the students to give them practice with grids is the game of Battleship.

1. Tape off a region of a tiled, linoleum floor (6'x 6' or so) to act as the grid area. If such a floor is not available, grid lines can be laid down with masking tape.

2. Label the lines of the grid with Post-it pads. To simplify the coordinate system, label one axis with letters ("A", "B", "C"...) and the other with numbers ("1", "2", "3"...).

3. Scatter various objects throughout the grid region. Books, blocks, toys, boxes all make good choices.

4. Give each student a sheet of graph paper. Have the students map the area on the graph paper, using the graph paper's grid as a scaled-down version of the grid on the floor. Have them compare maps and discuss results.

Discussion

Did the grid help to map the area? How? What kind of maps use grids? Do grids help on interstate highways maps? Why or why not? Are there any grids on the Earth with lines we can see like the ones on the floor?

Activity 4-11: Latitude and Longitude on the Earth

The dawn of the Great Age of Discovery, some five hundred years ago, greatly increased the demand for accurate maps and charts. The explorers needed maps which covered areas much more vast than those we have yet constructed; they required maps of nothing less than the entire world which they were exploring. Indeed, much of the work of these early explorers involved making newer, more accurate maps of little- or never-traveled regions.

Even still, it was not until about a century ago that a standard coordinate system to describe locations on the Earth's surface was adopted. An international convention devised the now-familiar system of latitude and longitude and fixed its reference points. As illustrated in the figure, a line of longitude (a meridian) passes through both the North and South Poles. They are labeled according to their angular distance from the prime meridian which passes through Greenwich, England by international agreement. Meridians are labeled between 0° and 180° East or West of the prime meridian. Lines of latitude (often called "parallels") are parallel to the Equator, and are labeled according to angular distance from the Equator- between 0° and 90° North or South. Any point on the surface of the Earth can be uniquely specified by just these two coordinates, latitude and longitude.

Materials: Globe or map of world and local maps with clearly marked latitude and longitude scales; list of cities (on world map) or landmarks (on local map) to find by latitude and longitude coordinates.

1. Make a list of several of places with their longitude and latitude for the students to find.

2. List a couple of places for each student or each group of students to find. See if they can identify the right place only knowing its longitude and latitude.

3. Have each student make a new list of places. The students can trade their lists and try to find the new places too.

Discussion

The lines of latitude and longitude are not straight, since they are on the surface of a sphere. Nevertheless, if one looks at a small enough region, like a city or a town, that region of the Earth is nearly flat, so the lines of longitude and latitude appear straight and seem to form a square grid. Note that close to the Poles, where the meridians converge, the slant of the meridians is quite noticeable, even on small scales, so even if they appear straight, they won't form a square grid.

Topic 4: Celestial Mapping

It is possible to determine your latitude and longitude from observations of the night sky wallpaper. Finding your latitude in the northern hemisphere is the easiest, as it only requires one night's observation of the Pole star. This figure shows a diagram of the Earth with the dashed lines denoting the Earth's equator and the axis of spin. We've placed a small figure of a person on the Earth to show someone observing from a city on the Earth. Notice that tracing the line straight up to the zenith point for this observer makes an angle with the equator which is the degrees latitude for this observer (since latitude is defined as the angle above or below the equator). Also notice that the horizon for this observer is marked as the diameter of the Earth perpendicular to the zenith line, or 90° below the zenith point in all directions, defined as such because you can look straight out as well as straight up. Thus, the equator of the earth, if extended up to the sky, is not on the horizon of this observer, but is above it by a number of degrees which are difficult to determine! So, how do we find out how many degrees from the equator, i.e.; degrees latitude, our city is? The figure below shows you that since you know the equator is 90° from the pole by definition and our latitude is 90° from our horizon by definition, that 90° minus our degrees latitude equals 90° minus the height (in degrees) of the Pole star over the horizon OR our degrees latitude equal the degrees of height of the pole star over the horizon! Using the fists method, students can count how many fists and fingers above the horizon they see the Pole Star and that is how many degrees above the equator they are!

Activity 4-12: Calibrating your fist

All you need to know is that 90° is the angle between holding your arm straight out to the side and straight out in front of you. All you need to do is stand still and put your arm out in front of you at eye level, with your hand in a fist. Close one eye. Carefully begin moving your arm stiffly, watching and counting how many fists you can line up side by side until your arm is 90° away from where you started, or straight out to your side. Use things around the yard as guides to help you count those imaginary fists. The figure helps you see what we are describing. Dividing 90° by the number of fists you counted will give you how many degrees your fist covers! (Hint: In case you are not sure of your answer, an average fist covers 10° on the sky. Your value should be close to this.) Similarly, you can try to calibrate your finger! But we will tell you that the human finger held at arm's length will cover 1° on the sky.

Activity 4-13: Measuring your latitude

Materials: Paper and pencil.

1. In the evening after the sun has set, students should face north, using their Big Dipper guide from Chapter 1. Students should locate Polaris.

2. Students place their fist straight out in front of them with the bottom of the fist resting on the horizon line. They should then count how many fists they can stack up before the top of their fist reaches Polaris.

3. Since the students have already calibrated their fists, they know that the number of fists they counted up to Polaris multiplied by how many degrees their fist will cover will give them the number of degrees up to Polaris, or their latitude! Write this down for reference.

Discussion

What kinds of values did the students get for their latitude? Checking with the real latitude of your town, how accurate were these measurements? Could the students find this fists method useful for measuring other heights? Distances between stars on the sky? Sizes of constellations? Diameter of the moon (1/2 °, or a pencil held at arm's length!)? Perhaps further night observations will allow students to make star atlases describing the constellations in terms of degree sizes on the sky.

Activity 4-14: Mapping the Sky

The visible stars can be used as markers on the sky which can be placed on a map. Such star maps are useful not only to astronomers trying to find a certain star with a telescope but also to children trying to find the Big Dipper. Making a map of the entire sky is similar to making a map of the entire world - both are round and too big to observe all at once, for example. It turns out that celestial maps use a coordinate system very similar to latitude and longitude of their terrestrial counterparts, but on a sky map these coordinates are called "right ascension" and "declination".

These activities can be used either to help students become familiar with constellations before locating them or to help reinforce their observations and help them learn. It may be useful to use these activities to introduce the concept of magnitude of stars. Magnitude is the term used to define the brightness of a particular star. The brighter the star, the lower the magnitude number. The brightest stars have magnitudes from negative numbers up to around 3. The brightest star we can see is Sirius in the constellation Canis Major, which is visible in January and February. It has a magnitude of -1.42. This star is labeled on the Star Map included in Activity 1 of this topic. Conversely, the fainter stars have higher magnitudes. A star whose magnitude is 6 is difficult to see without an optical aid. Also, stars differ in color. They range from the hottest which are blue, then green, white, yellow, orange and red, in descending temperature. Stars appear to twinkle although giving off steady light as our sun does because of the atmosphere of the Earth. Therefore , stars just above the horizon appear to twinkle more than stars up above us because we are viewing them through more density of the Earth's atmosphere at the horizon.

Discuss constellations and stars already found. What questions do students have? What would they name these patterns or individual stars if they were just discovering them and making order out of them? They may share their ideas about new shapes and configurations from existing star patterns. Some students may want to make up stories to give more meaning to their ideas or this could be a group activity. One person might begin to tell a story about his new creation/constellation and others add to it around a circle. Did the ancients tell stories this way? Without writing down the story, tell it again the next day or week. Does it change? What value would be gained from writing these stories down? What value might be lost?

Activity 4-15: Introduction to Mythology and Storywriting

This may be an appropriate time to introduce the study of Greek mythology since many of the constellations were named by ancient Greeks. After students have found many constellations the stories will capture their attention and have more meaning for them. Students may do research to find out about the Greek gods and goddesses such as Zeus, Athena, Hera, Apollo, Hermes and others. They may enjoy hearing myths as well as reading them. Perhaps they would enjoy hearing a story for each of the zodiac constellations. These are told in a beautifully illustrated book, The Shining Stars: Greek Legends of the Zodiac.. A companion book to this is The Way of the Stars: Greek Legends of the Constellations or Dauliere's Greek Myths (for older students). These are listed in the bibliography. Myths often were told because there was a problem that needed to be solved and it was solved within the myth. Students may write their own myths, creating their own gods, goddesses, and part god, part human characters. They too will work through their problems as they learn to write and develop their creativity. Myths often explained natural phenomena. This activity may be enlarged to hearing and discussing the elements of myths from different cultures. The comparisons show universality of themes across time and space. Students will find meaning by reading, listening, and writing these stories without extrapolating a moral or reason.

What is a myth? How does it differ from other stories? Why are there so many stories linking gods, goddesses and part god part human figures? What could ancient people have needed to tell, accomplish by telling stories about the constellations in the sky? If you don't know a story about a constellation could you make one up that has meaning?

Materials: Greek Myths and other myths from a variety of cultures

1. Students listen to a number of Greek Myths which relate to the constellations. They read some on their own and do research on the characters in these stories.

2. Students may write stories of their own choosing using existing gods, goddesses and heroes or creating new ones. They may imagine that they are in the time frame of the ancients and discuss the effect this has on their writing. What kinds of reasons might they have to write a story? ( i.e., explaining natural phenomena such as the occurrence of seasons or happens when people die?) Or do they just want to tell about how they feel about their lives and what is important to them?

3. Can they find examples of myths from other cultures which are about the cosmos? Are any of these similar to the ones told by the Greeks? Did any other cultures see the same configurations of constellations? Did they give them similar names? Perhaps students will continue to write stories based on other cultural mythology or they may wish to record stories they make up to go with an imaginary constellation configuration.

4. Students may record stories on tape, on the computer, or on paper. Sharing these stories out loud might be done in a circle at various times. If students tell their tales (rather than read them), they will be more expressive.

5. Students may wish to tell what this writing experience was like for them. What kinds of stories do people tell now? What about space stories? How has story telling changed? Why has this happened? What kinds of stories will people write in the future?

1. Students should find several bright stars on the map and noting colors and sizes.

2. They help to make a circle on the heavy paper by determining center and using yarn and chalk to circumscribe a five foot circle using radius of two and one half feet. They mark off eight equal sections, like pie pieces, or other pattern.

3. They make the same division into eight parts or more on the star chart and number each section on both circles. Try whenever possible to make the pie pieces along lines which do not cut off constellations.

4. Students copy stars (in pencil) and patterns from small to large map section by section. They mark over each penciled star in crayon to resist paint. Try to represent star sizes in scale and colors.

6. They represent star sizes, colors and positions by cutting stars of various sizes and colors of shiny papers and glue to maps.

7. They then cut direction labels; N, S, E, W out of silver paper and glue them as they are on the star chart, i.e., N on northern horizon, S on southern horizon, etc.

8. When dry, hang map on ceiling -- if possible, matching directions with the position of the school. If not possible to hang on ceiling, hang on wall as if facing northern horizon (north at bottom of circle).

9. Students use map to locate constellations without lines drawn between them and to identify various stars. They help other students to begin star studies.

Discussion

How did this compare to making an earth map? Did this help students to remember the star groupings and other stars? Could they locate the constellations? North Star? What other ways could they help others to learn what they have learned? How have people used stars for maps? In what other way could this new knowledge help them in their lives? Students may choose a constellation formation, draw it and make a new form out of it. What name would they give to it? Students may discuss their observations and share theories about stars, their magnitudes, sizes, and configurations.

Activity 4-17: Understanding Distance in Space

The function of this activity is to give the students an understanding that constellations are not flat pictures in the sky, but rather the product of three-dimensional space. The stars are so far away that they appear flat, as if forming a dome above the Earth. Constellations are patterns of stars. For the most part, they are named after characters or animals in mythology. They usually do not look like what they are named for. For instance, Pegasus doesn't resemble a winged horse at all and Cygnus the swan looks more like a cross. Some, such as Canis Major (the large dog), are easier to imagine. The question of whether the stars that make up a constellation are as close to each other as they appear in the sky is a puzzle for students to solve. They should ask themselves what would they see if one star was both next to and far back from another. They should also be wondering why the sky seems flat. The following activity will demonstrate how constellations really are positioned in space, and should give students a better definition of a constellation.

Materials: Large flat field; paper plates.

1. Number seven paper plates.

2. Hand out the plates to seven students. These plates will serve as stars.

3. Demonstrate the positions for holding the plates as the following:

LOW: The student sits with the plate at his/her feet.

CHEST: The student stands holding the plate at his/her chest.

FACE: The student stands holding the plate over his/her face.

HIGH: The student stands holding the plate over his/her head.

4. Using the diagrams as a guide, have the even numbered students line up about 30 feet from the rest of the class. Have the student with plate no. 2 stand on the far right (from the point of view of the rest of the class) with the plate at his/her chest. Have the student with plate no. 4 stand with the plate at his/her chest about 5 feet to the right of the student with plate no. 2. Have the student with plate no. 6 stand with the plate over his/her head 10 feet to the right of the student with plate no. 4.

5. Have the odd numbered students stand on a line about 20 feet from the rest of the class. Have the student with plate no. 1 sit in front of the student with plate no. 2 with the plate at his/her feet. Have the student with plate no. 3 do the same thing with respect to the student with plate no. 4. Have the student with plate no. 5 stand with the plate over hiss/her face about 5 feet to the right of student no. 3. Have the student with plate no. 7 stand with the plate over his/her face to the right of student no. 5.

6. Have the rest of the class look at the seven plates from a distance of about 20-30 feet with one eye shut. Do they see a flat or three-dimensional pattern?

7. Have the odds and evens switch lines so that all the odds are on the back line. Have the rest of the class look at them again. Do they see the same thing?

Discussion

What is a constellation? Are the stars in the sky all the same
distance from the Earth? Why do the stars appear to be flat in the
sky? What else could be in space besides stars? What do these other
objects do in space? Do objects in space move? Are there patterns to
the arrangement of the stars? to their movement?

Activity 4-18: Using Star Maps

Note: Finding groups of stars is easier when done with a guide to help. The maps included for this activity are fairly uncomplicated. However, when gazing at the stars, the sky looks much different because of the numerous additional stars visible.

Your students should be able to find the Big Dipper, North Star, and the Little Dipper from the exercises in Chapter 1. Now they will observe more constellations in the night sky.

1. Introduce students to the appropriate star map. Discuss using these at home and how to do so effectively. Try them out with students in the classroom using the directions given on the charts. It is important to hold this map so that the direction you are facing is pointing toward you if you are holding it horizontally, or is on the bottom if you are holding it vertically. Have students hold the chart in front of them and raise it above their heads to simulate the actual sky above them. Help them locate Ursa Major (the Big Dipper), Polaris, the Little Dipper, and Cassiopeia. What other constellations (if using November-December chart) do they think they can locate? Have them record observations in journals right after viewing.

2. Repeat star map activity with new chart for next two months throughout the year. Are students able to make better predictions to find constellations based on earlier observations? If given one map at a time after using two maps and locating constellations can they predict what the third map will include or not include? Will there be new constellations visible? How about the zodiacal constellations? Can they predict when the next one will appear on the map if given a diagram of the zodiacal procession of constellations?

3. Identify particular stars. If observing in September or October look for Vega in Lyra and Deneb in Cygnus. Mizar, which is the star at the bent part of the Big Dipper's handle, has a faint companion star which can be seen by many people without binoculars. If not, binoculars should reveal it.

Discussion

Discuss the observations as a group. Students may have been recording their activities in journals and this should help them to share more easily and accurately. Have the students share their records of the changing positions of the circumpolar stars (or dippers).

How can this pattern be useful to us? What do they notice about the other constellations over a period of time? What do they think is happening? Can they predict what the sky will look like a year from now? Why are some stars brighter than others? Different colors? Throughout this activity students may discuss, compare and predict results of these recordings. How helpful are these predictions to them in their understanding of the patterns of movement they observe in the stars? Are they able to predict the movement of the stars in the next months? Are they able to compare these observations with those form the seasons and the calendar? How can the pattern of the stars and planets help us keep records?

Activity 4-19: Making a Star Plotter

This activity is appropriate for students in grades 4-6.

Sky mapping is an active way to make an original guide to the sky.
Since students are actively engaged in this project, it will help them
to view and report findings accurately. A star plotter will help them
to chart the positions of the stars just as they see them in the sky.
This activity provides a means of illustrating changes in the
stars' positions. In this activity, students take records of where
the stars have been and when they were there. This activity adds to
their education of how the universe moves in orderly patterns.

Students may discuss stargazing experiences. How can they record
their experiences and select what they want to remember? How could
they use this information? How could they plot the stars and planets
to help them learn and remember more about patterns? To explain
observations to others?

1. Students may make a few star plotters to take turns using. To make: drill two 1/4-inch holes about at the middle of one side of the Plexiglas in about 1/2 inch. Attach the handle with wood screws or appropriate glue.

2. Discuss using these plotters. Outside, students must remember to find a place to rest the hand holding plotter to steady it on a tree or post. Then they can point the plotter to a section of the sky with many stars visible. They can make a mark for each object visible making them larger or smaller according to the brightness of the objects. Viewers should record on one corner of the Plexiglas, the direction in which viewing, the angle from the horizon (degrees such as 30°, 45°, 60° - see note in box following Activity 1 in this topic), the hour, and the date. When inside, tape tracing paper to plotter and trace marks onto it as well as the information on time, etc. Then clean the plotter. Make another map either in another part of the sky or in the sky or in the same area a few hours later.

3. Students may make a number of these maps of the same area of the sky at intervals over a period of months in order to record the movement of the stars.

4. They may also make maps of constellations with the plotter. Find one of the constellations already discovered with the sky map. Place the star plotter so that this constellation is in the middle of the Plexiglas square. Mark the stars of the constellation with the grease pen as in other plottings. Then add as many of the surrounding stars as possible. Remember to write in the direction, angle, date, and hour you observe. Then trace the dots on the plotter. Connect the stars in the constellation to make a pattern such as the one on the sky map and write the name. This is a more realistic depiction of the constellation as it appears in the sky than on a star map because it includes surrounding stars.

Activity 4-20: The Astrolabe

These activities are more appropriate for grades 4-6.

When students build and use the star plotter in Activity 2, they learn to estimate angles and distances in the sky using their fists. These measurements are not very accurate. To obtain more accurate figures, an instrument may be made to help determine measurements. This is an astrolabe which was invented by the Greeks and disseminated by Islam. This instrument was used to observe and calculate the position of celestial bodies before the invention of the sextant. This activity includes two models, one simple and the other more complicated to measure angles by the stars. It also includes an exercise in geometry using a clock to understand dividing circles into degrees and naming angles. This system of dividing circles into 360° is an ancient one. A circle of 360 equal parts can be divided into quarter circles (four quadrants) each containing 90 degrees. If using a clock for a model from 12 O'clock to three o'clock is 90 degrees. From 12 O'clock noon to 12 O'clock midnight is 360 degrees.

Polaris or the North Star is a place to start measuring the angle above the horizon. This angle is equal to the latitude at the point where the calculation is figured. Latitude refers to the parallel lines which are numbered from the equator at 0 degrees north to the pole (90 degrees north latitude) and south to the opposite pole (90 degrees south latitude). The latitude of the North Star is 90 degrees at the North Pole and overhead there. At the equator, it would be 0 degrees and visible if possible in a direct horizontal position. If one uses the complex astrolabe it is possible to calculate the position of other celestial bodies by comparing them to the position of Polaris. The complex astrolabe will help students to find constellations and make sky maps with the important stars in their correct positions as viewed from a particular latitude. An inexpensive (around $3.00) astrolabe is available from:

Science Kit, Inc.
777 East Park Drive
Tonawanda, NY 14150.

Is it helpful to have a system to measure the position of the stars and their height from where we stand? Would it help us to be more accurate in these measurements? How would a measurement made by fists compare numerically with one done by an instrument? How could we check for accuracy of results?

Materials: 8-1/2"x11" sheet of paper or 4' tube; protractor; small weight such as key; thread; tape.

1. Discuss measuring and the ancient use of an astrolabe to find the angle of the north star and other sky objects. This is called latitude. The system of measuring degrees can be introduced to students by using the clock as an example.

2. Use the tube or roll a paper into a 1/4" tube. Tape the protractor to the length of the tube. Tie a thread around the middle of the flat side of the protractor and attach the weight on the free end of the thread. Practice using this model in the classroom. If 0° represents the equator and 90° the position at the North Pole. Can you predict the latitude where you are?

3. At night, locate the North Star. Point the tube directly at it. Look through and find the star. Read the degrees on the protractor as you hold the string at that place. Do this a few times to make recording more accurate.

4. How can you check this information for accuracy? Did this instrument change the measurement that you determined or estimated? Can you devise another model to measure the position of objects in space? What other measurements can you make with this model? What differences do you think will occur in measurements of these objects from night to night? In one night, measuring at intervals, what changes do you observe and record?

1. Discuss astrolabe; its history and use. Then build one for testing. To build place the two thin strips of wood in a T shape and drill a 1/4 inch hole through the pieces. Fasten them together with the bolt and wing hut leaving it loose enough to move for sighting. Then attach (glue) a protractor to the cross stick centering it on the bolt exactly.

2. Attach this to the other piece of wood to form a base. Nail the support stick to the center of one of the long sides. Then cut a 12'' circle of heavy cardboard. Divide the circle into quadrants or corners by making two lines at right angles to each other through the center of the circle and mark the end of each of these lines with the directions North, East, South and West. Then divide the spaces between into three equal parts. Each of these represents 30°. Make a hole with a drill through the center of the base and circle. Attach the circle to the base with large metal paper fastener. Draw a line on the center of the base and mark one end North. Tape a drinking straw on top of the narrow strip forming the cross part of the "T". Line the straw up so that it is even with one end of the stick which is the sighting stick. Attach a thread to the bolt and tie the other end to the weight.

3. When finished, students can place this outside on a level place with the straw at eye level. After finding Polaris they should sight it through the straw. Since Polaris is always in the North, the circle can be turned so that the mark for North faces Polaris. Have a student locate another bright star. Leaving the wheel intact, he/she turns the sighting stick to face the star. Then he/she sights the star through the straw. It helps to use a flashlight covered with cellophane to read the direction in which the line on the base is pointing. That line tells you the direction and how many degrees the star is from due north. Then find where the thread crosses the protractor. This indicates the angle above the horizon or latitude. Students may record this information.

Discussion

After many experiences testing this model, students may discuss
experiences. In what ways did using this instrument prove helpful?
Was it easier to locate constellations with this instrument? Did
they record changes in position of stars over a period of hours? Days?
What did they discover. How could ancient people learn from this
instrument? How could this instrument help us if lost? Is this
instrument helpful in making sky maps with the Star plotter?